Chapter 20 - The Heart

Vocabulary flashcards for Chapter 20 - The Heart

Cardiovascular System Function

Transports nutrients, wastes, and hormones; regulates pH and temperature; protects against infection and blood loss.

Cardiovascular System Structure

Blood, heart, and blood vessels.

Arteries

Vessels carrying blood away from the heart

Veins

Vessels carrying blood to the heart

Circulatory System

Systemic circuit

Circulatory System

Pulmonary circuit

Heart Function

Pump blood.

Heart Structure

Two pumps (right and left), layers of pericardium, myocardium, endocardium; chambers of two atria and two ventricles; valves into and out of ventricles.

Pericardium Layers

Fibrous, parietal, fluid layer, visceral.

Myocardium

Muscular layer of the heart.

Endocardium

Innermost layer of the heart.

Atrioventricular Valves

Tricuspid and bicuspid (mitral).

Semilunar Valves

Pulmonary and aortic

Pericardium Function

Protects the heart and anchors it.

Fibrous Pericardium

Dense and non-flexible connective tissue layer of the pericardium.

Serous Pericardium

Parietal layer (attached to fibrous layer) and visceral layer (outer surface of the heart wall, also known as epicardium).

Pericardial Fluid

Lubricates the space between the visceral and parietal pericardium.

Layers of the Heart Wall (superficial to deep)

The epicardium (visceral pericardium), the myocardium (cardiac muscle tissue), and the endocardium (endothelium).

Upper Chambers of the Heart

Right and left atria.

Lower Chambers of the Heart

Right and left ventricles.

Right Heart

Right atrium and right ventricle; pumps deoxygenated blood from the body to the lungs.

Left Heart

Left atrium and left ventricle; pumps oxygenated blood from the lungs to the body.

Atrioventricular Valves Function

Allow blood to flow from atria into ventricles; prevent blood flowing from ventricles to atria

Outflow (Semilunar) Valves Function

Allow blood to flow from ventricles into arteries; prevent blood flowing from arteries to ventricles

Atrioventricular (AV) Valves

Right = tricuspid valve, left = bicuspid or mitral valve.

Outflow Valves (Semilunar Valves)

The right outflow valve (pulmonary valve) opens into the pulmonary trunk (pulmonary artery). The left outflow valve (also called the aortic valve) opens into the aortic arch (aorta).

Cardiac Muscle Tissue

Connect to and communicate with neighboring cells via gap junctions in intercalated discs.

Autorhythmicity

Form cardiac conduction system; myocytes spontaneously depolarize after repolarizing.

Sinoatrial (SA) Node

Normal pacemaker of the heart, located in the right atrial wall below the superior vena cava.

Cardiac Conduction

Spontaneous Depolarization of autorhythmic fibers in the SA node firing about once every 0.8 seconds, or 75 action potentials per minute

Cardiac Conduction System Pathway

SA node -> Internodal fibers -> AV node -> AV bundle -> Right and Left Bundle Branches -> Purkinje fibers -> regular myocardium in ventricles.

Electrocardiogram (ECG or EKG)

Recording of the electrical changes on the surface of the body resulting from the depolarization and repolarization of the myocardium.

P Wave

Atrial depolarization.

QRS Complex

Atrial repolarization + ventricular depolarization.

T Wave

Ventricular repolarization.

Cardiac Cycle

All events associated with one heartbeat, including diastole (relaxation phase) and systole (contraction phase) of both the atria and the ventricles.

Stroke Volume (SV)

Volume of blood ejected from the left (or right) ventricle every beat.

Cardiac Output (CO)

SV x heart rate (HR).

Cardiac Reserve

Difference between the CO at rest and the maximum CO the heart can generate.

Factors Affecting Stroke Volume

The amount of ventricular filling before contraction (preload), the contractility of the ventricle, and the resistance in the blood vessels (afterload).